jaxb-ri/runtime/impl/src/main/java/org/glassfish/jaxb/runtime/v2/runtime/NamespaceContext2.java

/*
 * Copyright (c) 1997, 2021 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0, which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

package org.glassfish.jaxb.runtime.v2.runtime;

import com.sun.istack.NotNull;

import javax.xml.namespace.NamespaceContext;

/**
 * Maintains {@code namespace <-> prefix} bindings.
 * 
 * <p>
 * This interface extends {@link NamespaceContext} and provides
 * an additional functionality, which is necessary to declare
 * namespaced attributes on elements. The added method is for
 * self-consumption by the marshaller.
 * 
 * This object is composed into a Serializer.
 */
public interface NamespaceContext2 extends NamespaceContext
{
    /**
     * Declares a new namespace binding within the current context.
     * 
     * <p>
     * The prefix is automatically assigned by MarshallingContext. If
     * a given namespace URI is already declared, nothing happens.
     * 
     * <p>
     * It is <b>NOT</b> an error to declare the same namespace URI
     * more than once.
     * 
     * <p>
     * For marshalling to work correctly, all namespace bindings
     * for an element must be declared between its startElement method and
     * its endAttributes event. Calling the same method with the same
     * parameter between the endAttributes and the endElement returns
     * the same prefix.
     * 
     * @param   requirePrefix
     *      If this parameter is true, this method must assign a prefix
     *      to this namespace, even if it's already bound to the default
     *      namespace. IOW, this method will never return null if this
     *      flag is true. This functionality is necessary to declare
     *      namespace URI used for attribute names.
     * @param   preferedPrefix
     *      If the caller has any particular preference to the
     *      prefix, pass that as a parameter. The callee will try
     *      to honor it. Set null if there's no particular preference.
     * 
     * @return
     *      returns the assigned prefix. If the namespace is bound to
     *      the default namespace, null is returned.
     */
    String declareNamespace( String namespaceUri, String preferedPrefix, boolean requirePrefix );

    /**
     * Forcibly make a namespace declaration in effect.
     *
     * If the (prefix,uri) binding is already in-scope, this method
     * simply returns the assigned prefix index. Otherwise a new
     * declaration will be put. 
     */
    int force(@NotNull String uri, @NotNull String prefix);
}